Portion of an electronic mouse



FIG. 1 is a front perspective view of a portion of an electronic mouse showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a right side view thereof; and,

FIG. 4 is a left side view thereof.

The unshown bottom forms no part of the claimed design. The broken line showing of various regions and the unshaded areas there within form no part of the claimed design. 

The ornamental design for a portion of an electronic mouse, as shown and described. 